Lt. T.J. Smith, Anne Arundel County Police spokesman, talks to the media outside the scene of a triple fatal shooting in the 1100 block of Armistead Street. Two men and one woman were found shot to death. Anne Arundel police say one of those killed, Christopher Lee Robinson, 37, of the 100 block of Glenview Terrace in Abingdon is the suspect in the incident.

Lt. T.J. Smith, Anne Arundel County Police spokesman, talks to the media outside the scene of a triple fatal shooting in the 1100 block of Armistead Street. Two men and one woman were found shot to death. Anne Arundel police say one of those killed, Christopher Lee Robinson, 37, of the 100 block of Glenview Terrace in Abingdon is the suspect in the incident. (Luke Broadwater, Baltimore Sun)

Luke Broadwater and Carrie Wells, The Baltimore Sun

Christopher Robinson was struggling to accept the end of his relationship with Marie Hartman, continuing to send her text messages and flowers even as his relatives told him he needed to move on.

Early Sunday morning, Robinson, a Baltimore police officer, went to the Glen Burnie home of Hartman's new boyfriend, Baltimore firefighter Andrew Hoffman, and fatally shot both of them before turning the gun on himself, according to Anne Arundel County police. Hartman's sister hid in a closet while she listened to the gunshots, her family members said.

The killings sent three families and two city agencies into mourning, left a 6-year-old boy without a mother and shocked the suburban neighborhood where Hoffman lived.

"That was my best friend," said an emotional Fred Scheper, 29, of Pasadena, who came to the neighborhood after he heard of the shooting. "He saved people's lives every day."

Wayne Robinson said it was clear that his brother was having a hard time getting over the August breakup, but that no one had any indication he would become violent.

"I don't know what happened last night, but the person that pulled that trigger wasn't the Chris that I know," said Wayne Robinson, also a Baltimore firefighter and a friend of Hoffman's.

"They told me this morning and I didn't believe it," he said. "I just couldn't wrap my head around the fact that it happened. I lost a brother and I lost a friend. It's just crazy."

Anne Arundel County police said Robinson, 37, of Abingdon, entered Hoffman's home at about 1:35 a.m. and shot the city firefighter and Hartman before taking his own life.

Lt. T.J. Smith, a spokesman for the Anne Arundel police, said investigators were "able to quickly determine this was a domestic-related murder-suicide."

"This is an absolute tragedy," he said.

Hoffman, 27, who grew up in the area and attended Glen Burnie High School, had recently begun dating Hartman, 26, and "was the happiest I've even seen him in his life in the past two months with the new girlfriend," Scheper said.

Ed Chaney, Hartman's stepfather, said she had dated Robinson "off and on" for more than a year. But after breaking up over the summer, Robinson became insistent that they get back together, Chaney said.

"About a month ago, she started saying that Chris was sending her text messages," Chaney said. "He wanted her back. He was saying, 'I love you. You and I need to be together.' Him being both in the Marine Corps and a city police officer, you don't think anything of it."

Wayne Robinson said his brother was trying to move on from the relationship, and learned a few weeks ago that Hartman had begun dating Hoffman. He also said that his brother continued to text her and send her flowers.

"He was having problems with this girl," Wayne Robinson recalled. "He asked me two weeks ago for advice. I told him to leave her be, because she didn't want anything to do with him anymore."

Still, he said, his brother was not confrontational and avoided "drama."

"I understand that he's the bad guy in this situation, but he wasn't a bad guy," Wayne Robinson said. "It's just unfortunate and very senseless."

Police have not released details of the incident, but Chaney said that on Saturday evening, Hoffman, Hartman and Hartman's 18-year-old sister, Brittany, attended a Halloween party, after which they picked up fast food and returned to Hoffman's house for a bonfire.

Chaney said the family believes Robinson followed them, and went to Hoffman's door in the 1100 block of Armistead Road. Chaney said Brittany told him Hoffman confronted Robinson, who "opened fire on Andy," Chaney said.

He said Brittany told him she hid in a closet and heard screaming and gunshots, then fled out a window. The two men, and her sister, were found dead by police.

Hoffman's family said in a statement that he died trying to protect Hartman and her sister.

"We have lost someone who meant so much to us and so many family members and friends," they said. "It's hard to imagine going forward without him, but we know Andy died a hero."

Wayne Robinson said his brother grew up in the Highlandtown neighborhood of Baltimore and joined the Marine Corps after high school, rising to the rank of sergeant. He was deployed in Okinawa, Japan, his brother said.

Baltimore police officials said there was "no indication" that Robinson's military service contributed to the incident, but said they began a review to see if "more can be done to help those returning to civilian life from military deployments."

Robinson's family members said they did not believe military service played a role in the incident.

Sunday's incident is the second time this year a Baltimore police officer, accused of a domestic homicide, has taken his own life, authorities said. In August, officer James Walton Smith, 49, awaiting trial for murder in the death of his fiancee, died in an apparent suicide in jail.

Police said both Baltimore Police Commissioner Anthony W. Batts and Anne Arundel County Police Chief Kevin Davis responded to the scene. Anne Arundel officers went door-to-door Sunday informing neighbors of the crime, and Smith said county officials removed Hoffman's dog from the home.

Neighbor Phil Sperlein, 58, said he was awakened by commotion around 1:30 a.m., when he saw a street full of police cars and officers "running around, yelling."

He described Hoffman as a "nice kid," who was "gregarious" and used to have friends over to play horseshoes. He said Hartman had been over at the house a lot in recent weeks.

"It's sad to say, but the gun culture that we got nowadays, everybody wants to solve their problems at the end of a pipe," Sperlein said. "I've got a temper, so I know I shouldn't own a gun."

Scheper, the close friend of Hoffman's, said when he first heard the news, he couldn't believe it.

"I thought it was fake," he said. "It's hit me, but it ain't hit me. I feel like he's still going to call me in a little bit, but that's not going to happen."

Fire Chief Jeffrey Segal issued a statement noting Hoffman was a "third-generation member of the Fire Department" who had been with the city department since 2006. "We offer sincere condolences to the Hoffman family as they grieve this terrible loss," he said.

Officials at the Baltimore Police and Anne Arundel Police departments also offered their condolences.

Segal noted this past July, Hoffman was credited with helping to reunite a 3-year-old toddler who had wandered from his home in Anne Arundel with his family. Hoffman had discovered Paul Marshall Jr. along the streets of Linthicum at 3:45 a.m. "It kind of startled me. " Hoffman told The Baltimore Sun. "I got him and asked him, 'What's the matter, buddy? Where do you live?'"

Hoffman and police tracked down the youngster's house. The boy's father, Paul Marshall, later thanked Hoffman, saying, "This really scared us thinking everything that could have happened."

The firefighter's family said that incident was one of several heroic acts in Hoffman's shortlife. "It was no surprise to us that Andy stopped to help that little boy," his family said in their statement. "Andy loved children and was a beloved uncle to his young niece and nephew."

Hoffman was awarded the 2010 Chief Thomas J. Burke Courage Medal for courageous acts in the line of duty for rescuing a man from a fire at 205 S. Gilmor St., according to his family.

On Sunday, the department's Fire Boat Station flew its flag at half-staff in mourning. Station 14 on Hollins Street, where Hoffman served, was draped in black.

"Andy Hoffman had one love and that was the Baltimore City Fire Department," said firefighters union president Rick Hoffman, who is not related but was close friends with him. "I cannot speak highly enough about this young man. He was the epitome of what I want to represent.

"He went out a hero," he said.

The union president recalled how a couple of weeks ago, Andrew Hoffman brought his new girlfriend to a union hall football tailgate to meet other firefighters. The two were happy together, friends and family said.

Dee Beatty, a friend of the Hartman family in Glen Burnie, said Marie Hartman aspired to one day become a police officer.

"Marie was an excellent mother," she said. "She was a beautiful girl. She was kind and caring and loving and she would help anybody. The sad part is a cop killed her and all she wanted to be was a cop."

Chaney described his stepdaughter, who was a project manager at a construction firm, as a "firecracker."

"She was always laughing. She was extremely happy with Andy," he said. "She came here two nights ago to carve pumpkins. She told us, 'This is serious between us.' We were happy for her."

Baltimore Sun Media Group reporter David Anderson contributed to this article.